Structural Constituents and Phases in High-Coercivity (Sm,Zr)(Co,Cu,Fe)z Alloys for Permanent Magnets

• Published in: Russian metallurgy Metally Vol. 2022; no. 5; pp. 505 - 511
• Main Authors: Dormidontov, N. A., Kolchugina, N. B., Prokof’ev, P. A., Zheleznyi, M. V., Milov, Yu. V., Dormidontov, A. G., Bakulina, A. S.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 2022; Springer Nature B.V
• Subjects: Chemical composition; Chemistry and Materials Science; Cobalt; Coercivity; Constituents; Cooling rate; Copper; Heat treatment; Iron; Materials Science; Metallic Materials; Permanent magnets; Quenching; Room temperature; Vacuum induction melting; Zirconium; high-coercivity state; rare-earth permanent magnets; heat treatment; Sm–Co system; nanoheterogeneous structure
• ISSN: 0036-0295; 1555-6255; 1531-8648
• DOI: 10.1134/S0036029522050032

(Sm,Zr)(Co,Cu,Fe) 6.0–6.8 alloys are prepared by vacuum induction melting and subsequently subjected to heat treatment in order to form a high-coercivity state, which includes annealing at 1160–1180°C for 5 h, quenching to room temperature, isothermal aging at 800°C for 20 h, and subsequent stepped tempering from 800 to 400°C at an average cooling rate of 100°C/h. The morphology and composition of main structural constituents of the alloys are studied by electron microscopy using samples in the form of individual grains separated from ingots. The hysteretic properties of the (Sm,Zr)(Co,Cu,Fe) z samples in the high-coercivity state are shown to correlate with the volume fractions of their main structural constituents, which, in turn, are controlled by the ratio of the 4 f -/4 d -/3 d -element contents in the chemical composition of the alloy.